Managing insect pests in ways that leave little or no toxic residues, have minimal impact on nontarget organisms, and are not prone to pest counter-adaptation (resistance) has always been challenge in modern agricultural systems.
Biopesticides can often fill these gaps, in some cases as stand-alone products. For example, some microbial biopesticides are used to kill mosquito larvae without contaminating the water in which they live. Such products have been proven to be a valuable and environmentally-friendly tool in public health programs to limit the spread of malaria, yellow fever, and other human diseases transmitted by mosquitoes. And, insect-parasitic nematodes (microscopic roundworms) are both highly specific and effective as a means for controlling soil-dwelling weevil larvae infesting citrus tee root systems.
Despite these prominent examples of stand-alone use, the more typical scenario involves the use of biopesticides as part of an overall integrated pest management (IPM) program. Typically such programs use microbial insecticides in rotations or tank mixes with traditional chemicals. Such programs focus more on maintaining insect pest populations below damaging levels than on providing quick fixes to pest outbreaks. Use of bioinsecticides also helps to extend the useful life of synthetic insecticides and to reduce the amount of unwanted pesticide residues in vegetable and fruit crops.